alac: simplify 1st order prediction and reading of warm-up samples

[ffmpeg] / libavcodec / mss1.c

diff --git a/libavcodec/mss1.c b/libavcodec/mss1.c
index 952737440b6fc140bf112bec3b75f35401c340eb..6eb9f1486ec54fc77ff445b395fe3212ab578879 100644 (file)
--- a/libavcodec/mss1.c
+++ b/libavcodec/mss1.c
@@ -499,7 +499,7 @@ static int decode_region_masked(MSS1Context *ctx, ArithCoder *acoder,
     dst  += x + y * stride;
     mask += x + y * mask_stride;
 
-    if (mask[0] != 0xFF)
+    if (mask[0] == 0xFF)
         dst[0] = decode_top_left_pixel(acoder, pctx);
     for (j = 0; j < height; j++) {
         for (i = 0; i < width; i++) {
@@ -557,7 +557,7 @@ static int decode_pal(MSS1Context *ctx, ArithCoder *acoder)
         *pal++ = (r << 16) | (g << 8) | b;
     }
 
-    return 0;
+    return !!ncol;
 }
 
 static int decode_pivot(MSS1Context *ctx, ArithCoder *acoder, int base)
@@ -783,6 +783,12 @@ static av_cold int mss1_decode_init(AVCodecContext *avctx)
     av_log(avctx, AV_LOG_DEBUG, "Encoder version %d.%d\n",
            AV_RB32(avctx->extradata + 4), AV_RB32(avctx->extradata + 8));
     c->free_colours     = AV_RB32(avctx->extradata + 48);
+    if ((unsigned)c->free_colours > 256) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Incorrect number of changeable palette entries: %d\n",
+               c->free_colours);
+        return AVERROR_INVALIDDATA;
+    }
     av_log(avctx, AV_LOG_DEBUG, "%d free colour(s)\n", c->free_colours);
     avctx->coded_width  = AV_RB32(avctx->extradata + 20);
     avctx->coded_height = AV_RB32(avctx->extradata + 24);